I think you need more than 50% to avoid penalty with most people aiming for 60% - there's a guy running a squad with something like 150% on the floor and he's seeing insane results so the bonus on this particular stat may not have a cieling

re: substitution - no. The substitution logic in the sim is flat-out terrible.

As for numbers on a penalty of bonus... can't say, really. I've never tested the penalty out. The bonus is relative to the type of defenses and tempos you face. The bonus will be higher in lower cap leagues where people can't stock up on as much defense. It seems that in the current $42m environment, getting 100 ast% (cumulative, 5 on floor) and up-tempo brings shooters to and maybe just above their RL averages. My testing is in extremely early phases, however, as the team I'm running this with just hit the all-star break and is in a division with a much better than average defensive team and several teams that are running slow-down on me. I've got a 125 ast% team that just started as well... results seem much better in it. jlg has several 150+ ast% teams either running or have run in the past... his results are way higher than what I've been getting. He's seeing guys with 15-20% increases (a 48% guy shooting 56%; a 60% guy shooting 72%).

I have a team that was decimated by RL injuries and am dipping this season into the 40 - 50's for cum ast%.
Assist numbers are definitely down (to no surprise), but I am seeing scoring and shooting percentage drops as well.
I think the norm of league appears to be 50-70, though there are a few teams that hit the 90's (and they do score alot).

Don't know if this is any help, but in a Prog. league, where I brought a fairly high ast% & averaged 32 apg my Jabbar shot 65% in both reg season & PO', the team shot 52%. In the same prog league but a different season where I had 30 apg Jabbar average 60.0 FG%, the team shot 50 FG%. I should note that on these teams I did not have a high ast player, the ast were gotten by committee, numerious 4-6 apg players.

it's a crap shoot game to game - Im fielding 100%+ as% on the floor per game (and running uptempo) in a draft league and after 2 games shooting 44% from the field from an IRL base of something like 51% - if only seasons were 1000 games long I'm sure it would average out in my favor but alas I only paid for 82 relatively random outcomes this time

Felonius, I have a team in the PPL prog league, that's @ 80 games played, it shot 46%fg for the first 30 games. Now at 80 games played it is at 51%fg. Sometime it a matter of distribution over 82 games. Does make for an annoying 30 games though.